My research in the Bonci lab focuses on studying the circuit of neurons that project from the dorsal raphe nucleus (DRN) to the ventral tegmental area (VTA). This circuit is important because studies in rats and mice have noted the DRN as the densest source of innervation to VTA dopamine neurons, yet the functional role of this circuit is very poorly understood. The DRN is the major source of ascending brain serotonin, and it has been presumed that the DRN->VTA circuit is serotonergic. However, in my research I have shown that this circuit is predominantly composed of non-serotonergic DRN projection neurons. Using optogenetic strategies in vivo and in slice electrophysiology, I have characterized the role of various non-serotonergic DRN neuron types in mediating reward. I have found that DRN non-serotonergic glutamate neurons are uniquely able to reinforce behavior this behavior is not supported by DRN serotonin, GABA, or dopamine neurons. The glutamate neurons project to the VTA and monosynaptically excite VTA dopamine neurons. I am finishing work on this project and plan to submit a manuscript in fall 2013. I am working on this project in collaboration with the lab of Dr. Marisela Morales. In addition to the above research, I contributed towards the research of Dr. Jonathan Britt, studying inputs to the nucleus accumbens. I was third author on the publication Synaptic and behavioral profile of multiple glutamatergic inputs to the nucleus accumbens (Neuron 2012;76(4):790-803.)